Current feed gases to a Claus process are typically limited to relatively low carbonyl sulfide (COS) concentrations, and it is generally believed that the COS concentration in the feed gas for a conventional Claus process can not exceed about 2% without significantly reducing the desulfurization efficiency, and/or compromising the flame temperature for destruction of contaminants (e.g., ammonia, aromatics, including benzene, toluene, and xylene, and/or hydrocarbons).
Consequently, numerous desulfurization processes are specifically configured to provide a feed gas with relatively low COS content to a Claus plant. Alternatively, and especially where the COS concentration in a feed gas is relatively high, hydrolysis of the COS in the fed gas using a TiO2 catalyst bed is often employed before the feed gas is fed into the Claus process. Exemplary configurations using pre-Claus COS hydrolysis are described in U.S. Pat. Nos. 4,735,788 or 6,113,872, both of which are incorporated by reference herein. While such processes generally reduce the COS concentration to levels that are considered suitable for known Claus plants, various disadvantages nevertheless remain. Among other things, COS hydrolysis generally requires relatively high capital and operating costs.
Therefore, although there are various configurations and methods known in the art to provide a feed gas with a relatively high COS content to a Claus plant, all or almost all of them suffer from one or more disadvantage. Consequently, there is still a need for improved Claus process configurations and methods.